Do you even think before posting?
What has the number of cars a ride runs got to do with being able to use lockers?
Harry Potter and the Forbidden Journey sends out a 4 person bench every 5 seconds, and has free lockers.
Revenge of the mummy has cars rather than trains, with a double sided load station, and sends out cars very frequently, and has free lockers.
Men in Black has two sides/tracks, with multiple 6 person shooter pods running along each track, and has free lockers.
All of these rides have you exiting separate to where you board.
Why is Scooby significantly different operationally?
The point is, you store your items before joining the main queue, just like Superman.
The free rental period is adjusted by the attendant to reflect queue times...On Dragon Challenge for instance, you had 25 mins when it had a 5 min queue (So long enough even for people wanting to use the front row queue and wait longer to get through in time)
When Potter had an hour queue, they pushed the rental time out to 80 mins.
People don’t use them as all day storage because of the cut off time (You get charged for staying longer), and because sometimes there is a short queue for the lockers anyway, so who can be bothered.